KR20020003447A - A process of preparing for the full dull polyester yarn - Google Patents

Abstract

PURPOSE: A process of preparing the titled fiber by producing the partially oriented yarn of a matt polyester at a high wind-up speed and then drawing at a draw ratio of no greater than 1.5 time is provided, which improves productivity, workability such as spinning and false twisting and quality of a yarn. CONSTITUTION: The polyester fiber is prepared by melt spinning of a polyester polymer containing 0.5% by weight or more of titanium dioxide, wherein 0.5 to 5.0% by weight of an orientation inhibitor is uniformly mixed with the above polyester in a molten state, spun and winded up at a speed of 5,000m/min or more to produce a partially oriented yarn, which is drawn at a draw ratio of no greater than 1.5 times. The glass temperature of the orientation inhibitor is 100deg.C or more.

Description

Matte polyester fiber and manufacturing method thereof {A process of preparing for the full dull polyester yarn}

The present invention relates to a method for producing a matte polyester fiber that can effectively delay the phenomenon that the crystallization on the radiation sharply increases when the high-speed spinning of the polyester fiber. Matte polyester fibers are made by adding at least 0.5% by weight of titanium dioxide during polymerization.

When spinning a polyester polymer at a high speed of more than 4,000m / min, the phenomenon of "Spinning Crystallinity" occurs due to the rapid increase in the radial tension, which causes severe process instability factors such as cutting and moor. The sex is significantly lowered. As a result, there is a limit of spinning speed during spinning of matt polyester fiber, and polyester partial alignment yarns which are currently mass-produced are usually manufactured at spinning speeds of 3,500 to 4,000 m / min.

At the spinning speed of 4,000m / min as the critical point, the increase in molecular orientation increases without increasing the crystallinity, but when the spinning speed exceeds 4,000m / min, the molecular orientation and crystallinity increase simultaneously. Therefore, as the spinning speed increases, the crystallinity increases rapidly with the increase of the radial tension and the alignment crystallization accordingly. As the spinning speed increases, the density and birefringence also increase. Ziabicki and H. Kawai Edited, 'High Speed Fiber Spinning', John Wiley & Sons, New York, 1985].

Until now, the process of delaying the rapid increase of the crystallization on the radiation by increasing the spinning speed in the polyester fiber production process overcomes the existing limit spinning speed and spins the polyester partial alignment yarn at a high speed of 4,000 m / min or more. Much research has been conducted on. Known methods to date can be roughly classified into first, through the modification of the raw polymer (copolymerization, molecular chain crosslinking, etc.) and second, by mixing the polymer material.

As a first method, EP 0 263 020 and US Pat. No. 4,518,744 add compounds pentaerythrite, trimethylropropane, melitic acid and trimellitic acid, which have side chains to the molecular chain, before or after transesterification or polymerization. US Patent 4,966,740 proposes a method for adding tetraethyl silicate before or after the transesterification reaction, US Patent 4,092,299 proposes a molecular chain crosslinking method using a tetrafunctional material have. However, the first methods must specifically select the polymerization conditions, and the workability in the draw combustion process is lowered. In particular, the high cutting rate in the combustion process causes a problem of difficult combustion.

As a second method, US Pat. No. 4,609,710 discloses a method of mixing polystyrene, polyamide, polymethylmethacrylate, or the like as a molecular alignment regulator during or after the polymerization of a polyester. In addition, a method of reducing the radiation orientation by adding a small amount of liquid crystal polymer material, polyethylene, polyethylene glycol, etc. in the conventional polyester polymerization is known. Appl. Polym. Sci., 31 , 2753 1986)]

In this case, the flowability of the polymer melt in the spinning process is drastically changed, which greatly affects the spinning characteristics, in particular, the spinning speed, thereby lowering the spun orientation. However, the method is difficult to spin stably due to the problem of uniformly mixing the added polymer, and the mixed polymer is moved to the fiber surface in the drawing and burning process to inhibit the workability, the occurrence of wool and fine dye stains Occurrence is a cause of deterioration of the final false twist quality.

In addition, when the matt polyester partial aligning yarn containing a large amount of titanium dioxide is stretched at a high draw ratio, it is highly likely that the draw rollers are flawed by the titanium dioxide present in the polyester polymer, which causes a lot of wool and the like, and thus the quality of the yarn. This was also reduced.

The present invention is to provide a method for producing a matte polyester fiber that can effectively delay the phenomenon of the rapid increase in crystallization on the radiation when spinning the matte polyester fiber at a winding speed of 5,000 m / min or more. In addition, the present invention is to provide a method for producing a matte polyester fiber that can prevent the growth roller to prevent damage caused by stretching, preventing the orientation of the crystal orientation to the fiber surface to reduce the yarn quality.

The present invention relates to a method for producing a matte polyester fiber which can effectively delay the spinning crystallization phenomenon during high-speed spinning of the polyester fiber, and excellent in drawing and flammability processability.

More specifically, the present invention is to prepare a polyester fiber by melt spinning a polyester polymer containing more than 0.5% by weight of titanium dioxide (TiO ₂ ), 0.5 to 5.0% by weight of the crystal orientation inhibitor in the molten state of the polyester polymer And uniformly mixed with it, followed by continuous spinning and winding at a rate of 5,000 m / min or more to produce a matt polyester partial alignment yarn, and the partial alignment yarn is drawn at a draw ratio of 1.5 times or less. It relates to a process for producing ester fibers.

Hereinafter, the present invention will be described in detail.

First, the present invention, when melt spinning a polyester polymer containing more than 0.5% by weight of titanium dioxide, 0.5 to 5.0% by weight of the crystal orientation suppressor of the thermoplastic resin is mixed with the polyester polymer in the molten state. If the titanium dioxide content in the polyester polymer is less than 0.5% by weight, the matte effect is lowered. As the crystal orientation suppressor, polymethyl methacrylate resin, polystyrene resin, or methyl methacrylate-styrene copolymer resin is used.

The glass transition temperature (Tg) of the crystal orientation suppressor is 100 ° C. or more. The reason is to maintain the difference in the solidification behavior of the polyester polymer having a glass transition temperature (Tg) of 80 ° C. on the radiation and the crystallization inhibitor, thereby suppressing the crystal orientation behavior of the polyester polymer.

If the glass transition temperature (Tg) of the crystallization inhibitor is less than 100 ℃, the difference in the solidification behavior between the polyester polymer and the crystallization inhibitor is small, it is difficult to effectively suppress the crystal orientation behavior of the polyester polymer on the radiation. As a result, the winding speed cannot be set to 5,000 m / min or more.

Due to the attractive force between the aromatic ring included in the crystallization inhibitor and the aromatic ring included in the polyester molecule, it is possible to more effectively inhibit the orientation crystallization occurring during the spinning and stretching process. It is well known that an aromatic ring is composed of double bonds between constituent carbon atoms, and therefore, an attractive force exists between adjacent aromatic rings.

In addition, the aromatic part is a rigid part inside the molecular chain, while the aliphatic part means a flexible part. Therefore, since an appropriate aromatic part can maintain the mechanical properties of the polymer chain which is a crystal orientation inhibitor, it plays a role of minimizing the loss of mechanical properties such as a decrease in strength due to the crystal orientation inhibitor fibrils distributed in the polyester. .

From this point of view, by using the crystallization inhibitor of the present invention, it is possible to maintain a similar level of physical properties, particularly strength, to the polyester partial-orientated yarn prepared by the general method.

The amount of the crystallization inhibitor added is 0.5 to 5.0% by weight based on the weight of the entire polymer (polyester polymer + crystallization inhibitor). If the added amount is less than 0.5% by weight, the effect of suppressing radiocrystallization is insignificant, and when the added amount is more than 5.0% by weight, the stretching and flammability processability deteriorate.

In the present invention, the mixing of the polyester polymer containing titanium dioxide and the crystal orientation suppressor is first supplied to the extruder and melted the polyester chip, and then the melted polyester is transferred to a two-stage twin screw extruder. At the same time as supplying the crystallization inhibitor chip (Chip) to melt and mix them. More preferably, the melt mixed in the two-stage twin screw extruder is continuously kneaded with a stationary kneader.

Meanwhile, the polyester polymer chip and the crystal orientation suppressor chip may be simultaneously supplied to an extruder to melt and mix them, and then the melt may be continuously kneaded with a stationary kneader.

The stationary kneader serves to make the crystal orientation suppressor distribution more uniform in the melt. In the case of the present invention, since a more uniform kneading is required, it is preferable to pass 20 or more stages of kneading kneader. In other words, kneading of 1 million (2 ²⁰ ) times or more is possible to uniform distribution of crystallization inhibitors, and is preferable to prevent the occurrence of salt spots in the false twisted state of the final product.

Otherwise, if the stationary kneader of less than 20 stages is adopted, deterioration of the quality may occur due to the occurrence of fine salt spots in the twisted yarn state, deterioration of workability in the stretching and combustion process, and stable workability There is a possibility of becoming difficult.

Next, as described above, the polyester polymer containing 0.5 wt% or more of titanium dioxide and the crystal orientation suppressor are uniformly melted and mixed, and then continuously spun and wound at a rate of 5,000 m / min or more to obtain a matt polyester partial alignment yarn. To prepare. The take-up speed increases productivity by 40% at least 5,000m / min. Winding speeds of less than 5,000m / min are marginal in productivity, and thus cannot be said to be economical in terms of return on investment.

In addition, the elongation at break of the partial oriented yarn wound at a speed of 5,000 m / min or more was 120% or more. When the elongation is more than 120% crimp frequency (Crimp Frequency) is high, the crimp quality can be obtained good twisted yarn, it is possible to secure excellent flammability workability.

Otherwise, it is difficult to perform high-speed operation more than 800 meters per minute in the simultaneous drawing and burning process, and it is difficult to obtain the same twisted yarn with the same physical properties as in the case of the simultaneous drawing and burning of the unstretched yarn spun at ordinary 3,000 to 3,500 meters per minute. It is difficult to secure the stability of the work by obtaining the combustible yarn which is deteriorated with Nice (CrimpLiveliness).

It is desirable to improve the radiation operability by using a ceramic guide having a high hardness during spinning to prevent damage to the guide due to titanium dioxide contained in the polymer.

In the present invention, it is preferable to maintain the shear rate in the spinneret during spinning at 7,000 to 15,000 per second. The shear rate in the spinneret during spinning is the dominant factor that determines the radial distribution of the crystallization suppressor distributed inside the spun yarn.

If the shear rate is low, the degree of orientation of the crystallization inhibitor in the fiber axis direction may be lowered, thereby reducing the effect of inhibiting the orientation crystallization of the matte polyester fiber. On the other hand, if the shear rate is too high, the crystallization inhibitor A problem arises that the distribution of is concentrated on the surface portion of the fiber, which may cause a problem of lowering the strength.

Therefore, if the shear rate in the spinneret is maintained in the range of 7,000 or more per second to 15,000 or less, the effect of suppressing the orientation crystallization of the matte polyester fiber is sufficiently exhibited, and the distribution of the crystallization inhibitor in the fiber radial direction is appropriately maintained. The strength of the oriented yarn and the false twisted yarn can be properly maintained.

Next, the matt polyester partially oriented yarn is stretched at a draw ratio of 1.5 times or less to prepare a matt polyester polyester yarn. In the case where the stretching ratio exceeds 1.5 times during stretching, a defect is likely to occur on the stretching roller due to a large amount of titanium dioxide contained in the polymer (fiber). In this way, if a flaw is formed on the stretching roller, a large amount of wool occurs in the yarn during the stretching process, and the quality of the yarn is degraded.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the present invention is not limited only to the following examples.

Example 1

Polyethylene terephthalate containing an intrinsic viscosity of 0.64 and 0.5 wt% of titanium dioxide was dried at 155 占 폚 for 4.5 hours. After melting the chip with a melt extruder, a continuous screw extruder having a glass transition temperature of 105 DEG C and 0.9% by weight of methyl methacrylate / styrene-based copolymer and 91.1% by weight of the polyethylene terephthalate melt (35 mm diameter twin screw extruder (temperature 300 ° C.). In addition, the fine kneading was continuously passed through a 20-stage stationary kneader.

Further, the polymer melt thus mixed is spun through 36 spinneret perforated spinnerets, and the cooling air at 22 ° C. is blown at a rate of 0.5 m per second to cool and solidify. An ester partial alignment yarn was prepared. At this time, the shear rate in the spinneret was 9,000 per second and the winding speed was 5,000 m / min.

The twisted yarn was manufactured using the Murada 33H (manufactured by Japan Murada Co., Ltd.) draw-synchronous combustor. The burning rate was 850 m / min, the draw ratio was 1.3 times, the temperature of the first heating plate was 200 ° C., the angle between the nip belts was 105 degrees, and the speed ratio was 1.5.

The final false twisted yarn was circular knitted using a circular knitting machine, and then dyed at 130 ° C. for 60 minutes using a disperse dye, and then dyeing quality of the plaque was examined. Table 2 shows the results of evaluating the fairness of spinning and combustibility and the properties of partially aligned yarns and combustible yarns.

Example 2 to Example 6 and Comparative Example 1 to Comparative Example 2

The same process as in Example 1 except that the content of titanium dioxide, the type of resin of the crystallization inhibitor, the glass transition temperature of the crystallization inhibitor, the mixed weight% of the crystallization inhibitor, the stretching ratio and the winding speed as shown in Table 1 Matte polyester partially oriented yarn, false twisted yarn and circular knitted fabric were prepared under the following conditions. Table 2 shows the results of evaluating the fairness of spinning, drawing and flammability and the properties of partially oriented yarn and twisted yarn.

Matte polyester partial alignment yarn manufacturing conditions division Crystallization Inhibitor Properties Titanium dioxide content (% by weight) Winding speed (m / min) Elongation ratio Resin type Glass transition temperature (℃) Addition amount (% by weight) Example 1 Methyl methacrylate-styrene copolymer 105 0.9 5.0 5,000 1.3 Example 2 Methyl methacrylate-styrene copolymer 105 2.5 6.0 5,300 1.5 Example 3 Polymethyl methacrylate 106 1.5 5.5 5,200 1.4 Example 4 Polymethyl methacrylate 106 3.5 6.5 5,100 1.2 Example 5 polystyrene 107 2.9 5.8 5,300 1.1 Example 6 polystyrene 107 4.0 6.2 5,500 1.4 Comparative Example 1 - - - 5.0 5,000 1.8 Comparative Example 2 Polymethyl methacrylate 106 0.1 6.0 5,500 1.6

Workability and Yarn Property Evaluation Results division Radiation workability Partial Incliner Elongation (%) Stretch workability Mouth occurrence Platter Example 1 Good 125 Good Almost none none Example 2 Good 132 Good Almost none none Example 3 Good 138 Good Almost none none Example 4 Good 143 Good Almost none none Example 5 Good 147 Good Almost none none Example 6 Good 123 Good Almost none none Comparative Example 1 Bad 83 Bad Occur a lot has exist Comparative Example 2 Bad 110 Bad Occur a lot has exist

The present invention effectively delays "radiation crystallization" in which the crystallization on the radiation increases rapidly during high-speed radiation, thereby producing a matt polyester partial alignment yarn at a winding speed of 5,000 m / min or more. As a result, productivity is improved. In addition, the present invention is uniformly mixed with the polyester polymer and the crystal orientation inhibitor is excellent in stretching and flammability processability. In addition, the present invention can effectively prevent the phenomenon that the crystal orientation inhibitor is moved to the yarn surface to reduce the yarn quality. In addition, the present invention can improve the quality of the yarn by minimizing the occurrence of scarring in the stretching process by stretching the partial orientation yarn at an appropriate draw ratio.

Claims (5)

In preparing polyester fibers by melt spinning a polyester polymer containing 0.5 wt% or more of titanium dioxide, 0.5 to 5.0 wt% of a crystal orientation inhibitor is uniformly mixed with the polyester polymer in a molten state, and then continuously After spinning and winding at a speed of 5,000 m / min or more to produce a matt polyester partial orientation yarn, the method of producing a matt polyester fiber characterized in that the partial orientation yarn is drawn at a draw ratio of 1.5 times or less. The method for producing a matt polyester fiber according to claim 1, wherein the crystallization inhibitor is a polymethyl methacrylate resin, a polystyrene resin, or a methyl methacrylate-styrene copolymer resin. The method of producing a matt polyester fiber according to claim 1, wherein the molten crystal orientation inhibitor and the polyester polymer are mixed with a stationary kneader. The method for producing a matt polyester fiber according to claim 1, wherein the molten polyester polymer and the solid crystal orientation suppressor are melted and mixed in a twin screw extruder. The method for producing a matt polyester fiber according to claim 1, wherein the crystallization inhibitor has a glass transition temperature of 100 ° C or higher.